Genetic Evidence that InhA of Mycobacterium smegmatisIs a Target for Triclosan

ABSTRACTThree Mycobacterium smegmatismutants selected for resistance to triclosan each had a different mutation in InhA, an enoyl reductase involved in fatty acid synthesis. Two expressed some isoniazid resistance. A mutation originally selected on isoniazid also mediated triclosan resistance, as did the wild-type inhAgene on a multicopy plasmid. Replacement of the mutant chromosomalinhAgenes with wild-type inhAeliminated resistance. These results suggest that M. smegmatisInhA, like its Escherichia colihomolog FabI, is a target for triclosan.